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Full text of "IS 4238: Sterilized Milk"

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sterilized Milk [FAD 19: Dairy Products and 



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Satyanarayan Gangaram Pitroda 
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PROTECTED BY COPYRIGHT 



Indian 




( Reaffirmed 1 999 ) 



Third Reprmt TANXJARY 1988 } 



IJT^C 637. 133.4 



© Copyright 1967 

BUREAU OF INDIAN STANDARI>S 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG 

NEW DELHI 1.10002 



LJfjT 



S>2piemher 1961 



Indian Standard 

SPECIFICATION FOR 
STERILIZED MILK 



Dairy Products and Laboratory Apparatus Sectional 
Gommittec, AFDC 34 

Chairman Representing 

Dr K. C. Sen Indian Dairy Science Association, Bai^alore 

Members 

Agricultural Marketing Ad- Diroitoratc of Marketing and Inspection (Ministry 
viSER TO THE GOVERNMENT OP of Food, Agriculture, Communtty Development 

India & Co-operation ), Nagpur 

SHKiB.S.DASZ(AltimaU) 
Shrx B. R. Bedekar Hindustan Milkfood Manufacturers Ltd, Nabha 

Chauuian Technical Standardization Committee ( Foodstuffs ), 

New Delhi 
Secretary (^/trmoite) 
Brio Ghandan Singh Directwate of Military Farms, New Delhi 

Shri Charan Dass ( 4/<^j)ta/0 ) 
Shri M. R. Chanorasbkhara Central Food Technological Research Institute 

{ CSIR ). Mysore 
Dr a. K. Ray Chaudhury Milk Commissioner, West Bengal 

Dr a. K. Sen Gupta ( Alternate ) 
Dr J. D. Contractor Kaira District Go-operative Milk Producers' Union 

Ltd, Anand 
Dr I. M. Patel {MtamaU) 
Dr N. N. Dastur Ministry of Food, Agriculture, Community Develop- 

ment & Co-operation, New Delhi 
Deputy Commissioner ( DD ) ( Alternate ) 
Director of Dairy Research National Dairy Research Institute, Karnal 

Shri G. S. Godbole Dairy Development Commissioner, Government of 

Maharashtra 
Shri N. D. Kotnis ( Alternate ) 
Shri I. K. Kapoor Directorate General of Technical Development, New 

Delhi 
Dr D. V. Karmarkar In peraonal capacity ( 5}31 Jangpura jB, New 

Delhi-14) 
Dr Zal R. Kothavala In personal capacity ( RusUm Bagh, HAL Road, 

Bangalore ) 
Dr A. P. Mahadevan Hindustan Lever Ltd, Bombay 

Dr K. K. G. Menon {Alternate) 
Dr R. N. Mathur Central Scientific Instruments Organization ( CSIR }, 

Chandigarh 

( Continued on page 2 ) 

BUREAU OF INDIAN STANDARDS 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARO 
NEW DELHI 110002 



IS:4238-1967 

( Continued from page 1 ) 

Members Representing 

Shri S. N. Mitra Central Cpmmittee for Food Standards ( Ministry of 

Health & Family Planning);, and Central Food 
Laboratory, Calcutta 
Shri D. S. Chadha ( Alternate ) Central Committee for Food Standards ( Ministry of 

Health & Family Planning ) 
Shri B. P. Palkhiwalla Poison Limited, Bombay 

Shri L. V. Dhruve ( Alternate ) 
Shbi Pr^m Prakash National Physical Laboratory ( CSIR ), New Delhi 

Shri N= P-angaswamy Glaxo Laboratories ( India ) Private Ltd. Bombay: 

and Indian Chemical Manufacturers* Association, 
Calcutta 
Representative Municipal Corporation, Bombay 

Shri F.J. Ryan Nestle's Products ( India) Ltd, New Delhi 

Dr M. K. K. Iyengar ( Alternate ) 
Shri C. R. Seetharaman Milk Commissioner, Government of Madras 

Dr L, C. Sikka Punjab Dairy Development Corporation Ltd, 

Chandigarh 
Shri Gurbhaowant Singh 
Kalhon ( Alternate ) 
Col C. I. So MAYA Food Inspection Organization, QMG's Branch, 

New Delhi 
Lt-Col N. G. C. Iengar ( AlternaU ) 
Shri James N. Warner In personal capacity ( Allahabad Agricultural Institute, 

Allafwbad ) 
Dr Hari Bhacwan, Director General, BIS ( Ex-officio Member ) 

Deputy Director ( Agri & Food ) 

Secretary 

Shri V. S. Mathur 

Assistant Director (Agri & Food), BIS, 

Milk Products Subcommittee, AFDG 34 : 1 

Convener 
Shri M. R. Srinivasan National Dairy Research Institute, Karnal 

Members 
Agricultural Marketing Ad- Directorate of Marketing and Inspection ( Ministry 
visER TO THE GOVERNMENT OF of Food, Agriculture, Community Development 

India & Co-operation ), Nagpur 

Shri B. S. Dane ( Alternate ) 
Dr J. D. Contractor Kaira District Co-operative Milk Producer' Union 

Ltd, Anand 
Dr I. M. Patel ( AlUmate ) 
Shri S, C. Das K. C. Das, Calcutta 

Shri R. N. Das ( Alternate ) 
Dr N. N. Dastur Ministry of Food, Agriculture, Gommumty Develop- 

ment & Co-operation, New Delhi 



Deputy Commissioner (DD) 
{ Alternate ) 



( Contimud on page 14 ) 



15:4238-1967 

Indian Standard 

SPECIFICATION FOR 
STERILIZED MILK 

0. FOREWORD 

0.1 This Indian Standard was adopted by the Indian Standards Institution 
on 16 August 1967, after the draft finalized by the Dairy Products and 
Laboratory Apparatus Sectional Committee had been approved by the 
Agricultural and Food Products Division Council. 

0.2 Sterilization of milk makes it completely free from viable bacteria and 
preservable in a sterilized container for consumption as fluid milk for a long 
period which may be even six months. Organized dairies in the country 
have, therefore, started the production of sterilized milk as it reduces the 
distribution cost considerably. This standard is being prepared to help 
these dairies in controlling the quality, as also for guiding other dairies to 
take up the production of sterilized milk. 

0.3 For preparing sterilized milk, raw milk is tested for quality and 
clarified or filtered to eliminate particles of dirt, dust, etc- The milk may 
then be homogenized at a suitable pressure and temperature. The product 
is then filled in clean bottles or cans. The containers are capped or sealed 
air-tight and placed in a sterilizer where the containers are gradually 
heated to a suitable temperature. The containers are then gradually 
cooled either in a current of air or water. 

0.4 Sterilized milk should remain stable for about 6 months. It should, 
therefore, be free from harmful micro-organisms and toxins, and should not 
show signs of bacterial growth during storage. 

0.5 In the formulation of this standard, considerable assistance has been 
derived from the following publications: 

Milk sterilization. Food and Agricultural Organization of the United 
Nations ( FAO ) Agricultural Studies No. 15, 1965. 

Laboratory manual. Milk Industry Foundation, Washington. 

IS : 1479 ( Part III )- 1962 Method of test for dairy industry : Part III 
Bacteriological analysis of milk. 

Manufacturing western dairy products in India. Indian Council of 
Agricultural Research Bulletin No. 49, New Delhi, 1958. 

0.5.1 The valuable information received from the National Dairy 
Research Institute, Karnal, is also acknowledged. 



18:4238.1967 

0.6 While fonnulating this standard, necessary consideration has been 
given to the relevant rules prescribed by the Government of India under 
the Prevention of Food Adulteration Act, 1954. However, this standard 
is subject to the restrictions imposed under this Act and the Rules framed, 
wherever applicable. 

0.7 For the purpose of deciding whether a particular requirement of thb 
standard is complied with, the final value, observed or calculated, express- 
ing the result of a test or analysis, shall be rounded off in accordance with 
IS : 2-1960*. The number of significant places retained in the rounded off 
value should be the same as that of the specified value in this standard. 



1. SCOPE 

1.1 This standard prescribes the requirements and methods of test for 
sterilized milk, 

2. TYPES 

2.1 Sterilized milk may be of the following types: 

a) Cow, : 

b) Bufialo, 

c) Standardized, 

d) Skimmed, 

e) Toned, and 

f) Double toned. 

2.1.1 The above types of milk shall be as defined in the Prevention of 
Food Adulteration Rules, 1955. 

3. REQ]UIR£M£NTS 

3.1 Sterilized milk shall be prepared from any of the types of milk 
mentioned in 2.1. It shall be white or creamy white in colour and free 
from abnormal taste or odour. There should be no separation of fat or 
sedimentation. It shall be free from any added colour or preservative. It 
shall be manufactured and packed under hygienic conditions as prescribed 
inIS:2491-1963t. 

3.2 The sterilized milk shall also comply with the requirements given in 
Tabic i. 

*Rules for rounding off numerical values ( r^m^^). 
tCode for sanitary conditions for food processing units. 



IS: 4238- 1967 



TABLE 1 REQUIREMENTS FOR STERILIZED MILK 

( Clause 3.2 ) 



No. 


Gharacteristic 


REqUlREMENT 


Method of Test 
( Ref to Appendix ) 


(0 


(2) 


(3) 


(4) 


i) 


Creaming index, Max 


20 


A 


") 


Turbidity test 


To conform to test 


B 


iii) 


Sterility: 








a) pH, variation on 7 days in- 
cubation. Max 


0-3 


C 




or 

b) Titratable acidity { variation 
on 7 days incubation ), g. Max 


0-02 


D 


iv) 


Bacterial spores, per millilitrc, 
colonies. Max 


5 


E 



4. PACKING AND MARKING 

4,1 Packing — The sterilized milk shall be packed in glass bottles or 
sanitary cans properly sterilized and stored in such a way as to protect it 
from contamination and deterioration. 

4JZ Marking — The following information shall be marked legibly on 
each container: 

a) Name of the material, 

b) Type of the product — * Cow/Buffalo/Standardized /Skimmed/ 
Toned/Double Toned milk '. 

c) Name and address of the manufacturer, 

d) Batch or code number, and 
c) Net content. 

4.2.1 Each container may also be marked with the Standard Mark 

NOTE — The use of the Standard Mark is governed by the provisions of the 
Bureau of Indian Standards Act, 1986 and the Rules and Regulations made there- 
under. The Standard Mark on products covered by an Indian Standard conveys 
the assurance that they have been produced to comply with the requirements of that 
standard under a well defined system of inspection, testing and quality control 
which is devised and supervised by BIS and operated by the producer. Standard 
marked products are also continuously checked by BIS for conformity to that 
standard as a further safeguard. Details of conditions under which a licence for 
the use of the Standard Mark may be granted to manufacturers or producers may 
be obtained from the Bureau of Indian Standards, 



IS:4238-1967 

5. SAMPLING 

5.1 Representative samples of sterilized milk for testing conformity tQ this 
standard shall be drawn as described in Appendix F. 

6. TESTS 

6.1 Tests shall be carried out as prescribed in the appropriate appendices 

given in col 4 of Table 1 . 

6.2 Quality of Reagents — Unless specified otherwise, pure chemicals 

shall be employed in tests and distilled water ( see IS : 1070-1960* ) shall 
lie used where the use of water as a reagent is intended. 

Note — ' Pure chemicals ' shall mean chemicals that do not contain impurities which 
affpct the test results. 

APPENDIX A 

ITahh \,Ttem (i) ] 
DETERMINATION OF CREAMING INDEX 

A-0. GENERAL 

A-0.1 Low creaming index is an indication of good homogenization. 
Sterilized milk may be graded as under for the quality of homogenization: 

Quality of Homogenization Creaming Index 

Excellent Up to 10 

Good 11 » 20 

Fair 21 "30 

Bad Over 30 

A-1. APPARATUS 

A-1.1 Glass Tubes — thiec, with ground glass stoppers, outside diameter 
24 mm; length with stoppers 245 mm (suitable for use with a 24-tube 
Gerber centrifuge ) ; and graduated from to 50 ml. 

A-1 .2 Pipette — three, fine pointed, connected to a suitable vessel and to 

a vacuum pump. 

A-1 .3 Apparatus for the Determination of Fat — as specified in 

IS: 1223-i958t. 

*Spocification for water, distilled quality ( revised). 

t Apparatus for the determination of fat in whole milk, evap»orated ( unsweetened ) miNc, 
separated milk, skim milk, buttermilk and (Trram by the Gcrb«r method. 



IS: 4238- 1967 
A.2. PROCEDURE 

A-2.1 Place 50 ml of the material at 20°± l^'C in each of the three tubes. 
Centrifuge for 15 minutes at 1 000 rev/min. 

A-2.2 Using the separate pipette, take 5 ml from the upper part of each 
of the three tubes, carefully taking the cream that adheres to walls of the 
tube and transfer into a container (sample I). Then empty the three 
tubes into a separate container ( sample II ). Measure the fat content in 
the samples I and II by the Gerber method as described in IS : 1224-1958* 
taking all the precautions required to be taken for homogenized milk that 
is, heating the sample at 65" + 2°C for 5 minutes in a water-bath after 
each centrifuging before taking the reading till identical readings are 
obtained. Usually three centrifugings are required each lasting for at 
least 5 minutes. 

A-3. CALCULATION 

Creaming index = = — x 100 

where 

A ~ fat content of the Sample I, and 
B ^ fat content of the Sample II. 



APPENDIX B 

[Table 1, Item (ii) ] 
DETERMINATION OF TURBIDITY 

B-1. APPARATUS 

B-M Water-Bath 

B-1. 2 Glass Test Tube — 16 X 160 mm size, perfectly transparent. 

B-1 .3 Erlemneyer Flask — 50-ml capacity, 

B-1 .4 Whatman No. 12 or Its Equivalent Filter Paper — 12*5-cm 
diameter. 

B-2. REAGENTS 

B-2.1 Ammonium Sulphate 

♦Determination of fat in whole milk, evaporated (unsweetened) milk, separated milk, 
skim milk, buttermilk and cream by the Gerber method. 



IS: 4238- 1967 

B-3. PROCEDURE 

B-3.1 Place in a 50-ml Erlenmeyer flask 4 g of ammonium sulphate and 
20 i; 0-5 ml of the sample at room temperature. Agitate the flask for 
about one minute until the ammonium sv.Iphate dissolves. Let the solution 
stand for at least 5 minutes, then filter it ihrough the pleated filter paper. 
Collect 5 ml of the filtrate in the glass test tube ( B-1.2 ). Place the tube in 
a boling water-bath. Examine the tube by moving it before a source of 
light from which the observers' eyes are screened. The filtrate should be 
clear. 

B^. INTERPRETATION 

B-4.1 Even a slight turbidity would indicate an insuflficicnt heat treatment 

given to the sterilized milk. 

APPENDIX C 

[Table 1, Item {iii) {a)] 

DETERMINATION OF pH 

CI. APPARATUS 

C-1.1 Incubator — adjusted at 55^ ± rC. 

G-1.2 pH Meter 

C-2. PROCEDURE 

G-2.I Determine pH of 30 ml of the sample in the flask, with a glass 
electrode at 20'*G and note the reading. Then incubate another 50 ml 
sample at 55° ± 1 "C for 7 days. Examine the flask each day, then shake 
and replace it in the incubator. If any physical alteration of the contents 
is observed ( coagulation with or without exudation, grittiness, floculation, 
formation of bubbles or scum, peptonization or proteolysis ) the result 
of the test shall be considered positive and the sample as non-sterile. 

G-2.1.1 If no alteration takes place during the 7 days incubation at 
SS^'C, remove the sample from the incubator and cool to room tempera- 
ture. Take a small portion of it and measure the pH in the pH meter 
with glass electrode at 20^G. From this pH value subtract the initial pH 
value (C-2.1). 

C-3. INTERPRETATION OF RESULTS 

G-3.1 Sample which does not show any physical alteration during incuba- 
tion at 55** ± 1 °C for 7 days and where the ^H does not show a difference 
of more than 0*3 unit from the initial j&H, is considered sterile. 

8 



ISt4238.1967 

APPENDIX D 

[Table 1, Item (iii) ( b ) ] 
DETERMINATION OF TITRATABLE ACaDITY 

D-1. APPARATUS 

D-IJ Incubator 

D-i.2 Burette — with soda-lime guard tube. 

D-1 .3 Porcelain Dishes — white hemishperical, of approximately 60-ml 
capacity. 

D-1 .4 Stirring Rods — of glass, flattened at one end. 
D-2. REAGENTS 

D-2.1 Standard Sodium Hydroxide Solution — 0*1 N. Prepare a 
concentrated stock solution of sodium hydroxide by dissolving equal parts 
of sodium hydroxide ( sticks or pellets ) in equal parts of water in a flask. 
Tightly stopper the flask with a rubber bung and allow any insoluble 
sodium carbonate to settle down for 3 to 4 days. 

Use the clear supernatant liquid for preparing the standard O'l N 
solution. About 8 ml of stock solution is required per litre of distilled 
water. The solution should be accurately standardized against acidic 
potassium phthalate or oxalic acid. 

D-2 .2 Phenolphthalein Indicator Solution — Dissolve 1 g of phenol- 
phthalein in 110 ml rectified spirit. Add 0*1 N sodium hydroxide solution 
until one drop gives a faint pink colouration. Dilute with distilled v.'atcr 
to 200 ml. 

D-2 .3 Rosaniline Acetate Stock Solution — Dissolve 0*1 2 g of rosaniline 
acetate in approximately 50 ml of rectified spirit, containing 0*5 ml of 
glacial acetic acid. Make up to 100 ml with rectified spirit. 

D-2.3.1 Bench Solution — Dilute 1 ml of the stock solution to 500 ml 
with a mixture of rectified spirit and distilled water in equal proportions 
by volume. 

Note — The' stock solution and the bench solution should be stored in dark brown 
bottles securely stoppered with rubber bungs. 

D-3. PROCEDUPJE 

D-3.1 Acidity of Fresh Sample — Weigh lO'O g of the sample into each 
of two white porcelain basins of approximately 60-rai capacity; add to 
both, 10 ml of water and stir to disperse the sample. Prepare from one 



IS:4238-1967 

dilution a colour control by adding and stirring 2 ml dilute rosaniline 
acetate solution. Stir 2 ml phenolphthalein solution into the other dilution 
and while stirring vigorously, add as rapidly as possible sodium hydroxide 
solution from a 10-ml burette fitted with a soda-lime guard tube, until the 
colour matches the pink colour of the control. The titration shall be 
preferably done in north daylight or under illumination from a daylight 
lamp. 

D-3.2 Acidity After Incubation ^- Incubate another 20 g of sample at 
55° d= I'^CI for 7 days. Examine the flask each day, then shake and replace 
it in the incubator. If any physical alteration of the content is observed 
( coagulation with or without exudation, grittiness, floculation, formation of 
bubbles or scum, peptonization or proteolysis ) the results of the test shall 
be considered positive and the sample as non-sterile. 

D-3.2. i If no alteration takes place during 7 days incubation remove 
the sample from the incubator and cool to room temperature. Weigh 10 g 
of the incubated sample and determine acidity as described in D-3.1. 

D-4. CALCULATION 

IM.l Acidity of Fresh Sample 

Titratable acidity ( as lactic acid ), 9 A N 
percent by weight = — — — 

where 

A — volume in ml of the standard sodium hydroxide required 
for titration (B^.l ), 

jV= normality of the standard sodium hydroxide solution 
(D-3.1), and 

W = weight in gram of the sample taken for the test ( D-3.1 ). 

D-4.2 Acidity After Incubation 

Titratable acidity ( as lactic acid ), 9 ^ jv" 
percent by weight = — jr^ — 

where 

A = volume in ml of the standard sodium hydroxide required 
for titration ( D-3,2.1 ), 

jV = normality of the standard sodium hydroxide solution 
(D-3.2.1), and 

vv = weight in gram of the sample taken for the test 
(D-3.2.1). 

10 



IS:4238.1967 

D-4.3 Subtract the value obtained in D-4.1 from the value obtained 
in II-4.2 which would give increase in acidity. 

D-5. INTERPRETATION OF RESULTS 

D-5.1 Sample which does not show any physical alteration during 
incubation at 55° -t 1°C for 7 days and where the acidity does not show a 
difference of more than 0'02 g from the initial acidity is considered sterile. 

APPENDIX E 

[ Table I, Item {i\)] 
DETERMINATION OF TOTAL BACTERIAL SPORES 

E-l. APPARATUS 

E-1.1 Dairy Bacteriological Pipettes — to deliver one millilitre of milk. 

Note 1 — Use of improperly cleaned pipettes may cavisc incompiete deliveries of test 
portions. To facilitate removal of milk solids, preferably rinse the pipettes immediately 
after use with water. After rinsing thoroughly, wash the pipettes with suitable detergents 
(such as alkyl sulphonate type or an alkaline phosphate) and then rinse until all 
detergent residues are removed. Exercise caution when using wetting agents for 
glassware washing as some of these have been found to adhere tenaciously and result in 
inhibiting growth. 

Note 2 — To ensure complete cleaning, soak the pipettes for 24 hours at weekly 
intervals, in strong cleaning solution and rinse several times with clean water. A 
cleaning solution may be prepared by dissolving 50 g of sodium or potassium bichromate 
in 200 ml of water in a glass or glazed earthen container, and then by adding cautiously 
with stirring 300 mi commercial sulphuric acid. 

Note 3 — Before use, test a few pieces of glassware in each batch for the presence of 
residual acid of alkali with appropriate indicator, such as bromothymol blue. 

E-1.2 Pipette Container — preferably of metal, may be round, square or 
rectangular, length about 400 mm. 

E-1.3 Petri Dishes — outside diameter 98 mm, inside diameter about 
94 mm; depth 15 mm, with flat bottom and free from bubbles, scratches 
or other defects. 

£-1.4 Petri Dish Containers — metal boxes with covers, cylindrical or 
square, for protection and convenient handling of dishes both before and 
after sterilization. 

E-1.5 Hot Air Oven — capable of giving uniform and adequate tem- 
peratures, equipped with a thermometer calibrated to read up to 220*^C, 
and with vents suitably located to ensure prompt and uniform heating. 

£-1.6 Autoclave — capable of providing uniform temperatures within the 
chamber up to the sterilizing temperature of 12 PC, equipped with 

11 



15:4238-1967 

accurate mercury-filled thermometer with bulb properly located so as to 
register the minimum temperature within the sterilizing chamber ( with or 
without temperature recording instrument ), pressure gauge and properly 
adjusted safety valve. 

E-1.7 Incubators — two, either water jacketed or anhydric type, 
electrically heated, thermostatically controlled and provided with shelves so 
spaced as to ensure uniformity of temperature; one maintained at 
30" ± 1"C and other 55^ ± TC. 

£-1.8 Hand Tally — a mechanical counting device. 

£-1 .9 Potentiometer or Comparator with Standard Colour Discs — 

for accurate determination of />H of media. 

£-1.10 Media Making Utensils — Natural, heat resistant glassware or 
other suitable non-corrosive equipment, clean and free from foreign 
residues or foreign material which may contaminate media, such as, 
chlorine, copper, zinc, aluminium, antimony and chromium. 

£-2. REAGENTS 

£-2.1 Prepare the solid media by dissolving the following ingredients in 
1 000 ml of distilled water: 

g 
Try p ton 10 

Yeast extract 3 

Glucose 1 

Soluble starch 1 

Agar, bacteriological grade 8 

After dissolving the above ingredients, adjust the pH to 7. Place in each 
200 X 20 mm tubes, about 20 ml of media. Sterilize in the autoclave 
for 15 minutes at 120°G ( or 1 kg cm^ steam pressure). Media may be 
stored at 4°C for not more than one month. 

£-3. PROCEDURE 

£-3.1 Pouring Plates — Add aseptically one millilitre of the sample to 
the petri dishes. Melt the agar medium in the boiling water-bath and 
cool to 45''C. Introduce 20 ml of the medium aseptically into the petri 
dishes within 5 minutes and mix by rotating and tilting the dish without 
splashing over edge. Spread the mixture evenly over the bottom of the 
plate. Allow to soHdify. 

£-3.2 Incubation — Invert the dishes and incubate at 30° :t ^°^ and 

55° ::t I'^C separately for 4 days in the incubator. 

£-3.3 Counting ~~ Count the colonics with the aid of hand tally. 

12 



15:4238-1967 

APPENDIX F 

( Clause 5.1) 

SAMPLING OF STERILIZED MILK 

F-1. GENERAL REQUIREMENTS OF SAMPLING 

F-1.1 Samples are required for chemical and bacteriological examination. 
All precautions shall be taken to prevent contamination and adulteration. 

F-1 .2 The sampling instrument shall be clean and dry. 

F-1 .3 For bacteriological purposes, all equipment including plungers, 
sample bottles and rubber stoppers, shall be sterile and the samples shall 
be drawn under aseptic conditions. All equipment shall be sterilized by 
cither of the following methods: 

a) Heating in a hot air oven for not less than 2 hours at 160°C, or 

b) Autoclaving for not less than 1 5 minutes at 1 20''C. 

F-2. SCALE OF SAMPLING 

F-2.1 Lot — In a single consignment all the bottles or cans containing one 
type of milk drawn from a single batch of manufacture shall constitute a lot. 

F-2.2 Samples shall be tested from each lot separately for ascertaining the 
conformity of the material to the required specification. 

F-2.3 If milk of uniform quality is supplied in containers, the number of 
units to be selected at random for sampling shall be in accordance with 
col 1, 2 and 3 of Table 2. 



TABLE 2 NUMBER OF CONTAINERS TO BE 

Number of Containers Number of C 

IN THE Lot t 

Bacterial Spores 

(1) (2) 

Up to 25 1 

26 „ 100 2 

101 „ 500 3 

501 „ 1000 3 

1 001 „ 5 000 4 

5 001 and above 4 


SELECTED FOR SAMPLING 

Iontainers to be Selected for 


Creaming Index, Turbidity 
and Sterility 

(3) 

1 

5 

7 

9 
11 
13 



F-2.4 The containers shall be selected at random and for this purpose a 
random number table shall be used. In case such a table is not available, 
the following procedure shall be adopted: 

Starting from any container count all the containers in one order as 
1, 2, 3... etc, up to r, and so on. Every rth container so counted shall be 
withdrawn where r is the integral part of Mjn ( N being the number of 
containers in the lot and n being the number of containers to be selected ) . 

13 



IS:4238.1967 

F^. TEST SAMPLES AND REFEREE SAMPLES 

F-?.l Preparation of Sample for Chemical Analysis — Mix 

thoroughly the contents of the containers selected according to col 3 of 
Table 2. Taking equal amount of sterilized milk from each selected 
container, collect about 200 g of the material which shall be mixed and 
divided into three equal parts. Each part is transferred to a clean and 
dry container and labelled. One of these samples shall be for the pur- 
chaser, the other for the vendor and the third for the referee. 

F-3.2 Preparation of Sample for Bacteriological Analysis — From 
the selected containers according to col 2 of Table 2, draw with suitable 
sampling instrument, which is sterile, at least 100 g of the material and 
mix thoroughly under aseptic conditions. Divide the sample ( taking care 
not to bring in microbiological contamination ) into three equal parts. 
Each part shall be transferred to sterile glass containers, sealed air-tight 
and labelled for bacteriological examination. One of these samples shall 
be for the purchaser, the other for the vendor and the third for the referee. 

F-3.3 Referee Samples — Referee samples shall consist of sample for 
chemical analysis and sample for bacteriological analysis. These shall be 
kept at a place agreed to between the purchaser and the vendor. 

F-4. CRITERIA FOR CONFORMITY 

F-4.1 The lot shall be considered as conforming to the standard if the test 
samples taken in F-3,1 and F-3.2 satisfy all the requirements of this 
specification. 



( Continued from page 2 ) 

Members Representing 

Director Central Food Laboratory, Calcutta 

Shri D. Ghosh Milk Commissioner, Government of West Bengal 

Shri H. p. Ray ( Alternate ) 
Shri I. K. Kapoor Directorate General of Technical Development, New 

Delhi 
Dr a. P.IMahadevan Hindustan Lever Ltd, Bombay 

Dr K. K. G. Menon ( Alternate ) 
Shri B. P. Palkhiwalla Poison Limited, Bombay 

Shri L. V. Dhruve ( Alternate ) 
Shri N. Rangaswamy Glaxo Laboratories ( India ) Pvt Ltd, Bombay 

Representative All India Ice Cream Manufacturers' Association, 

New Delhi 
Representative Central Food Technological Research Institute 

( CSIR ), Mysore 
Representative Government Analyst, Government of Madras 

Representative Parsi Dairy Farm, Bombay 

Representative Public Analyst, Government of Uttar Pradesh 

CoL G. I. SOMAYA Food Inspection Organization, QMG's Branch. New 

Delhi 
Lt-Gol N. G. G. Ie noar ( Alternate ) 
Shri Tames N. Warner In personal capacity ( Allahabad Agricultural Institute, 

■* Allahabad) 

14 



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^Strtl Ofli£« In BDmbifii fi N^wtptv Cl«tmb*ri, ^ttm Ht»id. B^ Si 38 

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Reprography Unit, BIS, Hew Delhi, India